This invention relates to ventilators, more particularly but not exclusively for use in rooms with sealed windows and/or double glazing where it is desirable to provide for ventilation without having to, open the window. This type of ventilation is now often referred to as "secondary ventilation" and has in recent years been achieved by means of a slot ventilator which is inserted into or positioned over a slot cut or formed in the surround of a window or the like. It is usual to provide at the inside end of the slot a manually operable ventilator closure or a grille while at the outside end it is usual to provide a canopy forming a lip extending outwardly and downwardly from the upper edge of the slot to resist the ingress through the slot of rain and other precipitation and to discourage the entry of dust and dirt and insects.
The present invention has as at its object to improve such canopies.